Haemophilus influenzae associated with acute respiratory illnesses in young children.

A total of 303 young children with acute respiratory tract illnesses were examined for viral and bacterial agents. The isolation of Haemophilus influenzae from 58 (19.1%) of the children was described in relation to respiratory viruses and other bacterial agents isolated at the same time. H. influenzae was isolated alone in 24 instances. Streptococcus pneumoniae and respiratory syncytial virus were the most common bacterial and viral agents associated with H. influenzae. Only 7.5% of the 40 laboratory confirmed cases of influenza yielded H. influenzae in their respiratory secretions.